LOW OIL PRESSURE

hello I just bought a 95 oldsmobile aurora with about 105,000 miles on it the problem is that the engine sound fine in fact it sound lovly but a low oil pressure indictaor comes on and the car keeps making this peep sound and the oil light comes on and when u start to drive the car it runs fine until u drive it for a long time this the car starts to over heat and all these gagues comes on so I pulled the car over and put some oil in it and when I started to drive it the same thing keep happening then after that white smoke came out the back when ever I had to stop and go again but when I put it on the highway no smoke but still the low pressure light comes on and when u cut the car off and wati awhile it starts back up fine no problem the problem is when u drive it for a while it starts to over heat and one more thing when u cut it off it makes this tick tick sound for like 10 seconds I think it is the oil pump thanks for your help